Mevalonate Kinase Deficiency

Mevalonate kinase deficiency (MKD) is an autosomal recessive inborn error of isoprenoid biosynthesis, a pathway yielding sterols and nonsterol isoprenoids.

In patients, the enzyme activity of mevalonate kinase is severely reduced due to mutations in the encoding gene, MVK. The substrate, mevalonate, accumulates and is elevated in blood and urine. Shortage of certain downstream products of the pathway, nonsterol isoprenoids, leads to dysregulation of the innate immune system, activation of inflammasomes, and interleukin (IL)-1 mediated inflammation.

Symptoms start in early childhood with recurrent attacks of fever, vomiting, diarrhea, headache, sore throat, abdominal pain, arthralgias, painful lymphadenopathy, hepatosplenomegaly, skin rash, and mucosal ulcers. Severely affected patients have additional symptoms, such as intellectual impairment, progressive cerebellar ataxia, and tapetoretinal degeneration. Complications include intestinal obstruction, AA-amyloidosis, hemophagocytosis, and severe infection.

Management of MKD is directed at controlling inflammation.